Field of the Invention
The present invention relates to an imaging apparatus using an imaging element having a plurality of photoelectric conversion units included in each pixel and a method for controlling the same.
Description of the Related Art
In recent years, multifunctioning for imaging apparatuses using an imaging element such as a CMOS (complementary metal-oxide film semiconductor) sensor or the like has been developed. Not only generation of still image data or moving image data but also control of an imaging apparatus such as focus adjustment are performed based on image information obtained by an imaging element.
Japanese Patent Laid-Open No. 2001-124984 discloses a technique that performs pupil division focus detection using an imaging signal obtained from an imaging element. One microlens and two photodiodes are provided for each pixel of the imaging element, so that each photodiode receives light fluxes transmitted through different pupil areas of an image-taking lens. Focus detection can be performed by comparing output signals from adjacent ones of the photodiodes and captured image data can be generated by summing these output signals.
When signals subjected to pupil division is acquired from a plurality of photodiodes included in each pixel, a phenomenon in which a signal from one photodiode leaks into the other photodiode may occur depending on the structure of the photodiodes upon a high intensity exposure. Consequently, signals subjected to pupil division may not be correctly read. In other words, the reliability of the signals acquired from the imaging element is decreased in a state in which light intensity is greater than a certain level, which may imperil exact focus detecting calculation.